The overall objectives of the proposed work relate to the study of essential fatty acid deficiency (EFAD) in man and animal with regard to (1) Changes in lipid profile and fatty acid composition of blood elements including platelets, and red and white blood cells. (2) Prostaglandin synthesis in platelets, functions and metabolism of parenteral nutrition with EFAD and during the course of linoleic acid (fat emulsion) administration. Specifically, the physiological, biochemical and metabolic functions of essential fatty acids will be investigated using blood elements as model cells in the EFAD state and during the course of linoleic acid (18:2w6) administration. (3) Effects of platelet stores of arachidonic and eicosatrienoic acids on prostglandin synthesis in platelets will also be studied. (4) The filtration phenomena of red blood cells, and chemotaxis, phagocytoses and superoxide production of white blood cells will be evaluated.